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Gulf oil spill: Time, money concerns led to BP's well design

June 14, 2010 |  4:57 pm

Documents released Monday by the House Energy and Commerce Committee offer the first direct evidence that saving money was on BP’s mind when the company changed its mind about the design of the well that is spewing oil into the Gulf of Mexico.

The oil giant opted eventually for a less complex design that some engineers have called inadequate and have blamed for the disaster that killed 11 men and started the worst spill in U.S. history.

BP has acknowledged that failure of cement or other sealing mechanisms in the well was a chief factor in the well blowout. But the documents give a more detailed picture of how BP engineers flip-flopped on the plumbing, finally choosing the low-cost option.

BP’s design for the failed well relied on just a single pipe, called a production casing, pushed down the center of the well and plastered in place by cement.

The documents released Monday revealed that BP initially rejected the single-pipe design based on the same concerns that experts have since raised: The skimpy design would need additional testing, and it would provide and open avenue for gas to travel up to the wellhead, BP’s engineers wrote in a report.

Instead, BP was set to rely on a more  conventional design using stacked double pipes, called a liner and tie-back. Several experts have said this more conventional design might have prevented the blowout.

But then came a flip: A subsequent report chronicles how engineers changed their minds after further simulations and switched back to the initial, skimpier design. Their investigations had found that the single-pipe option would seal the well successfully and meet regulatory requirements after all, the engineers wrote. Besides, they added, it represented “the best economic case.”

The single-pipe design would save $7 million to $10 million, another company report said.

In an internal e-mail released by the committee dated March 25, BP employee Brian Morel notes that using the single-pipe design “saves a lot of time … at least three days.” In a subsequent e-mail he adds that the design “saves a good deal of time/money as well as reduces complexity.”

BP’s documents show the company also considered a third possible design involving plugging the hole, but that this option would cost some $10 million to $15 million more.

To be sure, cost was not the only issue. In an e-mail exchange six days before the explosion, Morel once again raised the possibility of using double-pipe design in the well.

BP employee Richard Miller demurred, citing not financial but engineering concerns. The double pipe system, he wrote, carried the risk of pressure problems stemming from fluids expanding in the space between double pipes. A single pipe would eliminate this concern, he wrote.

But Miller added that the changes were causing confusion. “We have flipped design parameters around to the point that I got nervous,” Miller wrote, confiding that he had redone his calculations to make sure they were accurate and adequate.

BP’s internal report recommending the single-pipe well included a caveat that the design might require an extra test called a “cement bond log” used to detect anomalies in the cementing.

BP never performed this test, judging that the cementing went well enough to dispense with it.

The company saved itself about $118,000 by skipping the test, according to a document from Schlumberger, the bond-log contractor whose team was on deck to do the test. The team was sent home just before the disaster.

--Jill Leovy